1. Field of the Invention
This invention relates to methods for sealing capsules, using denaturation-melting point depression mixtures and thermal energy; and apparatus for sealing such capsules.
The capsules sealed by utilizing the present invention are telescopically joined capsules, having coaxial cap and body parts. The capsules are made of gelatin whose properties are pharmaceutically acceptable.
In this application, when the term "gelatin" is used, it is also understood to include other proteins similar to gelatin in physical and chemical properties.
In addition, capsules are sealed having a cap and/or body part made from a gelatin foam as disclosed in applicant's copending application U.S. Ser. No. 438,147 filed 10-29-82, now abandoned, the disclosure of which is incorporated herein by reference.
Foam capsules contain a microdispersion of a gas in a gelatin wall.
The capsule body and cap portions are formed by dip-molding the film-forming mixture obtained by a microdispersion of the gas in gelatin solution; optionally with the inclusion of a plasticizer and/or coloring agent, and/or flavoring agent, and/or foam stabilizer, and/or gelatin extender.
By a suitable choice of the gas proportion in the capsule wall and its micronization level, it is possible, within certain limits, to control the capsule wall disintegration speed and its opacity.
In addition, capsules were sealed by sealing fluids as disclosed in applicant's abandoned application U.S. Ser. No. 451,580, filed 12-20-82, the disclosure of which is incorporated herein by reference.
Hard shell gelatin capsules have a disadvantage when compared with other dosage forms, in that the cap and the body parts can be opened and rejoined without the disruption becoming externally visible or tamper-evident. Therefore, the consumer has no real guarantee that the contents of a capsule have not been tampered with.
Telescopically joined, capsules have only a partial overlap of the cap side wall over the body side wall which allows gripping and withdrawal of the body part, thereby making separation relatively easy. The present invention uses denaturation-melting point depression mixtures and thermal energy applied to the overlap of the cap side wall over the body side wall to prevent tamper-proofing by completely sealing the overlap of the capsule parts. In addition, when completely sealed, the capsules can be used for liquids without the problems of potential leakage.
1. Description of the Prior Art
Prior art for capsule sealing is contained in the following patents:
1. U.S. Pat. No. 3,071,513, issued Jan. 1, 1963 to H. R. DeBoer et al. which discloses a sealing fluid comprising a dispersion of an air-drying hydrophilic, film-forming polymer in an organic solvent. The application of the sealing fluid was by dipping the capsules.
2. U.S. Pat. No. 3,159,546, issued December 1, 1964 to J. R. Kane, discloses a liquid sealant consisting of three components containing by weight from about 1 to 41/2 parts, preferably 3 to 41/2 parts, of acetone; from about 11/2 to 2 parts, and preferably 11/4 to 2 parts, of water; and from about 3/4 to 21/4 parts, and preferably about 3/4 of a part, of ethyl acetate. The application of the liquid solvent was by drop application.
3. U.S. Pat. No. 2,924,920, issued Feb. 16, 1960 to Elly T. Margolis, discloses a three components mixture containing a polyhydric alcohol, an alcohol and water. This composition is used to seal capsules by a swelling technique. The process is designed to avoid solvent penetrating the overlap between capsule body and cap.
4. French Pat. No. 2,118,883, issued June 6, 1975 to Green Cross Corporation, discloses the use of alcohol and water in an enteric coating process.